I think he had high functioning autism and was antisocial, while having a terrible gambling addiction. It culminated with an overwhelmingly enabled access to firearms. Whenever he had big losses at the Casinos it felt like the whole system was conspiring against him. A major blow to his ego, intelligence, and personal values. High functioning autism explains a lack of empathy for victims. It also explains why he made mathematic systems for gambling. In the end it was symbolic for him to shoot at people at a Casino on the Las Vegas strip.

I think he got to this point where it seemed there's no real way of holding onto that one big sort of gambling reward. The gambler's high. Something about the idea of doing a mass shooting must have came to mind and when it did...it turned him on...Not sexually but more like the wires in his brain crossed and he felt surges of dopamine. He felt thrilled. The shooting for him would be like climbing Everest. This is the only thing I can compare it to here. It would also be a way for him to get back at the Casinos for all the perceived damage his losses were. He took gambling extremely personal. The gambling high was replaced by the sudden accumulation of guns and the planning. This would work for him because unlike gambling he would never feel the loss. He wouldn't come down from this high. A mass shooting and ending his life at a high note would world. In this atheistic age we live in there's no Heaven and no Hell, so why would he care about the consequences? One bullet to the head would be like flicking the off switch in life. C'est la vie. It was to be the most peak experience existence had to offer and then he could just die. Not necessarily die a happy man but die while in this manic delusional lucid experience of feeling like a God.